My airtel number has been discontinued

[immastermind]

They will ask you to take up the same number as a postpaid connection

But they didn't ask or told anything like that.They only told that come after 90days.

 

[hike]

I'll advice you to tweet about same happened with one of my relatives Vi sim but later it gets reactivate in prepaid after getting store visit.
After 90 days, they'll ask to take postpaid connection with same number and run it atleast for 3 billing cycle before turning it into prepaid.
That is the reason they sent you back, although your number will be not available for other customer till 90 days.